In 1887, two small children were found alone near the town of Banjos, Spain. But these were no ordinary children who had been lost or abandoned by parents. Upon investigation, they found a small boy and girl, scared and crying, huddled near the entrance to a cave. Their language was unknown to the workers - it certainly wasn't Spanish. More mysterious still, they wore clothes made of a strange metallic cloth... and their skin had an odd green tint.